Acer ALTOS 3102RS User Manual
AcerAltos 3102RSAcerAltos 3102RS
Ultra-SCSI to Ultra-SCSI RAID Controller
User’s Guide
CopyrightCopyright
Copyright 1998 by Acer Inc. All rights reserved. No part of this
publication may be reproduced, transmitted, transcribed, stored in a
retrieval system, or translated into any language or computer
language, in any form or by any means, electronic, mechanical,
magnetic, optical, chemical, manual or otherwise, without the prior
written permission of this company.
DisclaimerDisclaimer
This company makes no representations or warranties, either
expressed or implied, with respect to the contents hereof and
specifically disclaims any warranties, merchantability or fitness for any
particular purpose. Any software described in this manual is sold or
licensed "as is". Should the programs prove defective following their
purchase, the buyer (and not this company, its distributor, or its dealer)
assumes the entire cost of all necessary servicing, repair, and any
incidental or consequential damages resulting from any defect in the
software. Further, this company reserves the right to revise this
publication and to make changes from time to time in the contents
hereof without obligation to notify any person of such revision or
changes.
ii
FCC Class B Radio FrequencyFCC Class B Radio Frequency
Interference StatementInterference Statement
Note:
This equipment has been tested and found to comply with the limits for
a Class B digital device, pursuant to Part 15 of FCC Rules. These
limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee
that interference will not occur in a particular installation. If this
equipment does cause harmful interference to radio or television
reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or
more of the following measures:
1. Reorient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment into an outlet on a circuit different from
that to which the receiver is connected.
4. Consult the dealer or an experienced radio/television technician
for help.
Notice 1:
The changes or modifications not expressly approved by the party
responsible for compliance could void the user's authority to operate
the equipment.
Notice 2:
Shielded interface cables, if any, must be used in order to comply with
the emission limits.
iii
Table of ContentsTable of Contents
Chapter 1 Introduction ..................................................1
Chapter 2 Features.........................................................3
Chapter 3 Functional Description.................................7
RAID Management..........................................................................7
What are the RAID levels?.................................................7
NRAID Disk Spanning...................................................8
JBOD Single Drive Control............................................9
RAID 0 Disk Stripping....................................................9
RAID 1 Disk Mirroring .................................................10
RAID (0+1) Disk Striping with Mirroring ......................11
RAID 3 Disk Striping with Dedicated Parity Disk.........12
RAID 5 Striping with Interspersed Parity.....................13
Drive Failure Management............................................................ 14
Global and Local Spare Drive...........................................14
Identifying Drives..............................................................16
Automatic Rebuild and Manual Rebuild ...........................18
Automatic Rebuild.......................................................18
Manual Rebuild ...........................................................19
Concurrent Rebuild in RAID (0+1)....................................20
Disk Array Parameters ..................................................................21
Rebuild Priority .................................................................21
Verify-after-Write..............................................................21
Cache Parameters.........................................................................23
iv
Optimization for Sequential or Random I/O......................23
Drive-Side SCSI Parameters .........................................................24
SCSI Motor Spin-up..........................................................24
SCSI Reset at Power Up...................................................24
Disk Access Delay Time...................................................25
SAF-TE Enclosure Management ...................................................26
What is SAF-TE?..............................................................26
How Does SAF-TE work?.................................................26
Dynamic Logical Drive Expansion..................................................27
What Is It and How Does It Work? ...................................27
Two Modes of Dynamic Logical Drive Expansion.............27
Example: RAID Expansion in Windows NT
Server ................................................................30
Chapter 4 Hardware Installation................................. 39
Locations of the Parts ....................................................................39
Front View ......................................................................39
Rear View of the Main Board............................................40
Top View of the Main Board..............................................41
Top View of the Daughter Board (AA-9073UWS).............42
Top View of the Daughter Board (AA-9072UWD) ............42
Top View of the Daughter Board (AA-9073U2).................43
Installing DRAM SIMM...................................................................44
Installing the SCSI Channel Upgrade Daughter Board..................45
Battery Backup...............................................................................47
Power Connection..........................................................................50
Serial Port Connection and Set-Up................................................51
Basic Operational setup.................................................................53
v
In-band SCSI.................................................................................55
What is it and why do you need it?...................................55
How Do You Configure the Acer RAID Manager
to Use In-band SCSI? .......................................56
RAID Controller Adjustments......................................56
Example: Settings for Windows NT 4.0 ......................58
Using In-band SCSI in Acer RAID Manager..................... 60
Local Connection — SNMP Not Required ..................60
Remote Connection — SNMP Required.....................60
Chapter 5 Quick Setup.................................................67
Front Panel....................................................................................67
RS-232 Terminal Interface ............................................................ 69
Chapter 6 Configuring RAID........................................71
Starting to Build a RAID System Drive ..........................................71
How the RAID Controller Works?..................................................73
SCSI Channel, SCSI ID and LUN.....................................73
Understanding Step by Step............................................. 74
Chapter 7 General Front Panel Operation..................77
Understanding the Information on the LCD................................... 77
The Initial Screen..............................................................77
Logical Drive Status..........................................................78
SCSI Drive Status.............................................................79
SCSI Channel Status........................................................80
Viewing and Editing Logical Drives................................................82
Creating a Logical Drive...................................................82
vi
Viewing Logical Drives and Drive Members......................84
Deleting a Logical Drive....................................................84
Partitioning a Logical Drive ...............................................85
Deleting a Partition of a Logical Drive...............................86
Assigning a Logical Drive Name.......................................87
Rebuilding a Logical Drive ................................................88
Viewing and Editing Host LUNs .....................................................90
Mapping a Logical Drive to a Host LUN............................90
Viewing and Deleting LUN Mappings................................91
Pass-through SCSI Commands........................................91
Viewing and Editing SCSI Drives...................................................93
Scanning New SCSI Drive................................................93
Viewing Drive Information.................................................94
Adding a Local Spare Drive ..............................................95
Adding Global Spare Drive................................................96
Identifying a Drive .............................................................96
Deleting Spare Drive (Global / Local Spare Drive)............97
SCSI Drives Utilities..........................................................98
SCSI Drive Low-level Format......................................98
SCSI Drive Read/Write Test.......................................99
Viewing and Editing SCSI Channels............................................100
Viewing and Redefining a Channel Mode.......................100
Setting a SCSI Channel’s ID / Host Channel..................101
Viewing a SCSI Channel’s ID ...................................101
Setting a SCSI Channel’s Primary ID / Drive
Channel............................................................103
Setting a SCSI Channel’s Secondary ID / Drive
Channel............................................................104
vii
Setting a SCSI Channel’s Terminator ............................105
Setting the Transfer Speed ............................................106
Setting the Transfer Width .............................................107
Viewing and Editing a SCSI Target / Drive
Channel...........................................................108
Slot Number ..............................................................108
Maximum Synchronous Transfer Clock....................108
Maximum Transfer Width..........................................109
Parity Check..............................................................109
Disconnecting Support..............................................110
Maximum Tag Count.................................................110
Restoring the Default Setting ....................................111
Viewing and Editing Configuration Parameters...........................112
Communication Parameters........................................... 112
Caching Parameters.......................................................112
Write-Back Cache Enable/Disable............................112
Optimization for Sequential / Optimization for
Random ...............................................................113
viii
Host-side SCSI Parameters...........................................113
Maximum Queued I/O Count ....................................114
LUNs per Host SCSI ID.............................................114
Drive-side SCSI Parameters.......................................... 114
SCSI Motor Spin-Up..................................................115
SCSI Reset at Power-Up...........................................115
Disk Access Delay Time ...........................................116
Tag Command Queuing............................................116
SAF-TE Enclosure Monitoring...................................117
Detection of Drive Hot Swap Followed by Auto
Rebuild.................................................................117
Idle Drive Failure Detection.......................................118
Disk Array Parameters....................................................119
Rebuilding Priority.....................................................119
Verification on Writes................................................ 119
Controller Parameters.....................................................121
Controller Name........................................................121
Viewing and Editing Peripheral Devices.......................................122
System Functions.........................................................................123
Mute Beeper....................................................................123
Changing the Password..................................................123
Resetting the Controller ..................................................124
Viewing System Information.........................................................125
Viewing and Editing Event Logs...................................................126
Chapter 8 RS-232C Terminal Interface .................... 127
Understanding the Information on the Screen .............................127
The Initial Screen............................................................127
Main Menu ....................................................................128
Logical Drive’s Status......................................................129
SCSI Drive’s Status.........................................................130
SCSI Channel’s Status....................................................132
Viewing the Current Setting of Each Function ................134
Viewing and Editing Logical Drives..............................................136
Creating a Logical Drive..................................................136
Viewing Logical Drives and Drive Members....................139
ix
Deleting a Logical Drive..................................................140
Partitioning a Logical Drive.............................................140
Deleting a Partition of a Logical Drive ............................141
Assigning a Logical Drive Name.....................................142
Rebuilding Logical Drive.................................................143
Viewing and Editing Host LUNs...................................................145
Mapping a Logical Drive to a Host LUN .........................145
Viewing and Deleting the LUN Mappings.......................148
Viewing and Editing SCSI Drives.................................................150
Scanning a New SCSI Drive...........................................150
Viewing Drive Information...............................................151
Adding a Local Spare Drive............................................152
Adding a Global Spare Drive..........................................153
Identifying a Drive...........................................................153
Deleting a Spare Drive (Global / Local Spare
Drive)...............................................................154
Viewing and Editing SCSI Channels............................................155
Redefining a Channel Mode........................................... 155
Viewing and Editing a SCSI ID / Host Channel .............. 156
Adding a SCSI ID......................................................157
Deleting a SCSI ID....................................................157
Setting a Primary Controller’s SCSI ID / Drive
Channel...........................................................158
Setting a Secondary Controller’s SCSI ID / Drive
Channel...........................................................160
Setting a SCSI Channel’s Terminator ............................161
Setting a Transfer Speed ...............................................162
Setting a Transfer Width ................................................163
x
Viewing and Editing SCSI Target / Drive Channel..........164
Slot Number..............................................................165
Maximum Synchronize Transfer Clock.....................165
Maximum Transfer Width.........................................166
Parity Check..............................................................166
Disconnecting Support.............................................. 167
Maximum Tag Count ................................................ 167
Restoring the Default Setting....................................168
Viewing and Editing Configuration Parameters............................169
Communication Parameters...........................................169
Caching Parameters.......................................................170
Write-Back Cache Enable/Disable ...........................170
Optimization for Random or Sequential I/O.............. 171
Host-side SCSI Parameters............................................172
Maximum Queued I/O Count....................................172
LUNs per Host SCSI ID ..................................................172
Drive-side SCSI Parameters...........................................173
SCSI Motor Spin-Up .................................................173
SCSI Reset at Power-Up..........................................174
Disk Access Delay Time........................................... 174
Maximum Tag Count ................................................ 175
Disk Array Parameters....................................................176
Rebuild Priority.......................................................... 176
Verification On Writes...............................................177
Controller Parameters.....................................................178
Controller Name........................................................178
xi
System Functions........................................................................179
Mute Beeper................................................................... 179
Change Password..........................................................180
Changing the Password............................................181
Setting a New Password...........................................181
Disabling the Password.............................................182
Reset Controller..............................................................182
Viewing System Information........................................................183
Chapter 9 Redundant Controller............................185
Before You Begin.........................................................................185
What Is Redundant Controller? Why The Need For
Redundant Controller?.........................................185
Write-Back Cache: Enabled or Disabled?.................185
What are Primary controller and Secondary
controller? ............................................................186
When should I choose Primary, Secondary or
Autocfg mode?.....................................................186
Quick Start ................................................................187
Setting Up Redundant Controllers...............................................188
Example of Redundant Controllers ................................188
Cables and Connections ................................................189
Connecting the Redundant Controller Cable.............189
Connecting the Controllers to the Terminal
Interface...............................................................190
Connecting the SCSI Cable to the Host Computer...190
Connecting the SCSI Cables to the Hard Drives.......191
Setting the Controllers using the Front Panel.................192
xii
Redundant Configuration using Automatic Setting...192
Redundant Configuration Using Manual Setting....... 193
Starting-up the Redundant Controllers ..................... 195
Assigning Logical Drives to the Secondary
Controller.............................................................196
When One of the Controller Fails.................................................198
What will happen when the one of the controllers
fails? .................................................................... 198
When and How is the Failed Controller Replaced?.. 198
Chapter 10 Redundant Host, Multiple Host............. 201
Redundant Host...........................................................................201
Multiple Host.................................................................................202
Chapter 11 Remote Administration.......................... 203
Acer RAID Manager Using SNMP Service .................................204
How to Establish Connection through SNMP? .........204
Remote Terminal Emulation Using PPP+Telnet..........................206
Hardware Connection...............................................206
Baud Rate Settings................................................... 207
Enable Terminal Emulation.......................................208
Setting PPP ID, PPP Password................................ 208
Data Routing Through PPP, Data Routing Direct to
Port......................................................................210
Establish Connection Between the Host Computer
and AA-3102RS................................................... 211
Connect Telnet to the Controller’s IP from the Client
Computer.............................................................212
xiii
Remote Terminal Emulation Using Modem.................................213
Hardware Connection for AA-3102RS ......................214
Setting AA-3102RS using the RS-232C Terminal
Interface...............................................................214
Configuring the Modem Port.....................................215
Modem Initialization Command.................................216
Modem Operating Modes..........................................216
Sending Default Init command and Custom Init
command - “Append to Default”...........................217
Initializing Modem......................................................217
Baud rate, Data Routing and Enable Terminal
Emulation.............................................................218
Establish the Connection from the Remote Terminal219
How do you know the modem is connected?............219
Setting AA-3102RS Using the Front Panel ...............219
Configure Modem Port..............................................219
Modem Initialization Command.................................220
Modem Operating Modes..........................................221
Initializing Modem......................................................222
Baud Rate, Data Routing and Enable Terminal
Emulation.............................................................222
Establish the Connection from the Remote
Terminal...............................................................222
How do you know the modem is connected?............223
Dial-out for Event Notifications.................................................... 224
Dial-out to a Terminal or a Pager?............................224
Setting Dial-out Function Through the Terminal
Emulation.............................................................225
xiv
Dial-out Command....................................................225
Auto Dial-out on Initialization.....................................226
Dial-out Time out ......................................................226
Dial-out Retry Count .................................................227
Dial-out Retry Interval............................................... 227
Dial-out on Event Condition......................................228
Setting Dial-out Function Through the Front Panel ..229
Dial-out Command....................................................229
Auto Dial-out on Initialization.....................................230
Dial-out Timeout .......................................................230
Dial-out Retry Count .................................................231
Dial-out Retry Interval............................................... 231
Dial-out on Event Condition......................................231
Chapter 12 Fault-Bus ................................................ 233
What is Fault-Bus? Why the Need for Fault-Bus?.......................233
How Does the Fault-Bus Work?...................................................235
Error Signals Input....................................................235
Drive Failure Signals Output..................................... 236
Fault-Bus Error Alert .......................................................237
How to Setup the Fault-bus?........................................................238
Hardware ....................................................................238
Configuring the Controller through the Front
Panel................................................................238
Assign Each SCSI Drive or Canister a Slot Number 238
Assign a Slot Number to an Existing SCSI Drive......238
Assign a Slot Number to an Empty Canister ............239
xv
Delete the Slot Number.............................................240
Remove Empty Drive Entry.......................................240
Set Each Fault-bus Error Signal Input as Active-high
or Active-low.........................................................241
Enable Each Fault-bus Error Signal Input.................241
Test Drive Failure LED for Each Drive Canister........242
Viewing the Status of Each Fault-bus Error Signal
Input.....................................................................243
Viewing the Status of Each Fault-bus Error Signal
Input.....................................................................243
Configuring on the Controller through the RS-
232C Terminal Interface..................................244
Assign Each SCSI Drive or Canister a Slot Number.244
Assign a Slot Number to an Existing SCSI Drive......244
Assign a Slot Number to an Empty Canister.............245
Add Drive Entry .........................................................245
Delete the Slot Number of a SCSI Drive or Empty
Drive Entry ...........................................................246
Remove Empty Drive Entry.......................................247
Set Each Fault-bus Error Signal Input as Active-high
or Active-low.........................................................248
Enable Each Fault-bus Error Signal Input.................249
Test Drive Failure LED for Each Drive Canister........249
Viewing the Status of Each Fault-bus Error Signal
Input.....................................................................250
Appendix A Front Panel Navigation Map
Appendix B SCSI Cable Specifications
xvi
Appendix C Upgrading the Firmware
Appendix D Sync. Clock Period & Sync. Clock
Frequency
Appendix E Troubleshooting Guide
Appendix F Pin Assignments
Appendix G Specifications
Appendix H Record the Settings
xvii
Chapter 1 Introduction
The AA-3102RS is an Ultra-SCSI to Ultra-SCSI RAID controller
specifically designed to provide RAID 0, 1, 3 or 5 capability to any host
system equipped with a SCSI interface. It is totally independent of the
host system's operating system. All RAID functions are performed by
a 486 CPU coupled with high-speed DRAMs and firmware in the
Flash Memory. In effect, it endows the host system with a high speed
and fault-tolerant disk storage operation using the RAID technology. It
is an ideal solution for weaving several hard disks into one contiguous
volume.
The controller has comprehensive drive failure management that
allows automatic reassignment of reserved blocks when a bad sector
is encountered during a write. Hot-swapping is supported through
automatic disconnection of a failed drive and detection of a reserved
drive followed with background rebuilding of data. The controller also
supports spare drive operation. What’s remarkable is all these failure
recovery procedures are transparent to the host system.
The controller has been designed with ease of integration and
maintenance in mind. All major features are described in the next
chapter. The AA-3102RS already includes all the major operational
requirements of a RAID subsystem. The overall features of a fullybuilt RAID subsystem will, however, depend on the actual components
used and the creativity of the integrator.
Chapter 1 Introduction 1
Chapter 2 Features
The AA-3102RS has the following features:
• Five operating modes:
• Non-RAID Disk Spanning
• RAID-0 Disk Striping
• RAID-1 Disk Mirroring and Striping (RAID 0+1)
• RAID-3 Disk Striping with Dedicated Parity
• RAID-5 Multiple Block Striping with Interspersed
Parity
• Comprehensive failure management including:
• Automatic bad sector reassignment
• Hot-swapping
• Spare drive operation (Supports both Global Spare and
Local Spare)
• Background rebuilding (Rebuild priority selectable)
• Verify-after-Write supported on normal writes, rebuild writes
and/or RAID initialization writes
• Works with any operating systems without additional software
drivers
• 5.25" drive profile allows easy integration into external subsystem
enclosures or directly into the host system's drive bay
• Up to five drive channels (optional 3-channel upgrade) for a total
of 75 connected drives
• Supports up to 15 SCSI IDs per channel
• Three optional upgrade daughter boards:
• AA-9073UWS: Ultra Wide, single-ended, 3 SCSI channels
Chapter 2 Features 3
• AA-9072UWD: Ultra Wide, differential, 2 SCSI channels
• AA-9073U2: Ultra2 Wide, 3 SCSI channels
• Up to 8 logical drives, each with independent RAID modes
• Up to 8 partitions per logical drive
• Logical drive can be assigned a name for ease of identification
• Number of drives for each logical drive has no limitation
• Dynamic mapping of LUNs to logical drives. Two or more LUNs
can be mapped to the same logical drive for redundant host
operation
• Concurrent/Background logical drive initialization
• Performance optimization for Sequential or Random I/O
• Allows multiple drive failure and concurrent multiple drive rebuild
of a RAID (0+1) logical drive
• Configuration of individual SCSI target parameters
• Controller can be assigned a name for ease of identification
• Prior to first disk access, it allows adjustment of delay time during
controller initialization to enhance compatibility with slow-initial
drives
• All channels are Ultra-Wide SCSI-2 (downward compatible to
SCSI-1) and can be configured as either a host or drive interface
• Two or more SCSI channels can be simultaneously set as host
interface for redundant host system operation
• Compatible and will automatically match any SCSI hard disks with
SCSI-1, SCSI-2 or (Ultra)-Wide-SCSI (1 or 2) specification
• Full Ultra-Wide-SCSI-2 implementation including Tagged
Command Queuing and Multi-Threaded I/O
• Uses 486 CPU with all executable firmware downloaded into
high-speed DRAM
• EDO DRAM supported for enhanced performance
4
User’s Guide
• Up to 128 Mbytes of intelligent Read-Ahead/Write-Back cache
with optional battery backup
• Optional battery backup module to protect data in Write-Back
cache when a power failure occurs:
• AA-9010: battery backup module
• AA-9070: battery backup daughter board that connects to
AA-9010
• Firmware resides in easy-to-update Flash Memory
• Front panel LCD and push buttons for configuration and message
display
• Modem supported on either of the COM port
• Supports TELNET with PPP protocol for remote administration
• Acer RAID Manager and RS-232 terminal interface for RAID
management
• SAF-TE support
• Supports Fault-bus for enclosure management
AA-3102RS, mentioned throughout this
manual refers to both the AA-3102RSA and
AA-3102RSB controllers. The only difference
between them is: AA-3102RSA is a half-height
form factor with 2-line LCD display while AA3102RSB is a full-height form factor with 4-line
LCD display.
Chapter 2 Features 5
Chapter 3 Functional Description
The advantages of RAID are: Availability, Capacity and Performance.
Choosing the right RAID level and drive failure management can
increase Availability, subsequently increasing Performance and
Capacity. The AA-3102RS RAID controller provides complete RAID
functionality and enhanced drive failure management.
RAID Management
RAID stands for Redundant Array of Inexpensive Drive. The
advantages of using a RAID storage subsystem are:
• Provides disk spanning by weaving all connected drives into one
single volume.
• Increases disk access speed by breaking data into several blocks
when reading/writing to several drives in parallel. With RAID,
storage speed increases as more drives are added.
• Provides fault-tolerance by mirroring or parity operation.
What are the RAID levels?
RAID
Level
NRAID Non-RAID 1 Drive Drive
RAID 0 Disk Striping N ==RAID R: Highest
RAID 1
(0+1)
Description Minimum
Mirroring Plus
Striping
(if N>1)
Drives
N+1 >>NRAID
Data
Availability
==RAID 5
Performance
Sequential
W: Highest
R: High
W: Medium
Performance
Chapter 3 Functional Descriptions
Random
R: High
W: Highest
R: Medium
W: Low
7
RAID
Level
RAID 3 Striping with
RAID 5 Striping with
Description Minimum
Parity on
dedicated
disk
interspersed
parity
NRAID Disk Spanning
Drives
N+1 >>NRAID
N+1 >>NRAID
Data
Availability
==RAID 5
==RAID 5
Performance
Sequential
R: High
W: Medium
R: High
W: Medium
Performance
Random
R: Medium
W: Low
R: High
W: Low
NRAID
Minimum
Disks required
Capacity N
Redundancy N
1
o
+
+
+
=
Logical
Drive
2 + 3 + 1 + 2 = 8 GB Logical Drive
2 GB Hard Drive
3 GB Hard Drive
1 GB Hard Drive
2 GB Hard Drive
NRAID stands for Non-RAID. The capacity of all the drives are
combined to become one logical drive (no block striping). In other
words, the capacity of the logical drive is the total capacity of the
physical drives. NRAID does not provide data redundancy.
8
User’s Guide
JBOD Single Drive Control
JBOD
Minimum
1
Disks
required
Capacity 1
Redundancy No
2 GB
Logical Drive
3 GB
Logical Drive
1 GB
Logical Drive
= 2 GB Hard Drive
=
=
1 GB Hard Drive
3 GB Hard Drive
2 GB
Logical Drive
=
2 GB Hard Drive
JBOD stands for Just a Bunch of Drives. The controller treats each
drive as a stand-alone disk, therefore each drive is an independent
logical drive. JBOD does not provide data redundancy.
RAID 0 Disk Stripping
Logical Drive
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
.
.
Minimum Disks required 2
Capacity N
Redundancy No
Block 1
Block 3
Block 5
Block 7
RAID 0
Physical Disks
Striping
.
.
Block 2
Block 4
Block 6
Block 8
.
.
Chapter 3 Functional Descriptions
9
RAID 0 provides the highest performance but no redundancy. Data in
the logical drive is striped (distributed) across several physical drives.
RAID 1 Disk Mirroring
Logical Drive
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
.
.
Physical Disks
Block 1
Block 2
Block 3
Block 4
.
.
Mirroring
Mirror 1
Mirror 2
Mirror 3
Mirror 4
.
.
RAID 1
Disks required 2
Capacity N/2
Redundancy Yes
RAID 1 mirrors the data stored in one hard drive to another. RAID 1
can only be performed with two hard drives. If there are more than two
hard drives, RAID (0+1) will be performed automatically.
10
User’s Guide
RAID (0+1) Disk Striping with Mirroring
Physical Disks
Logical Drive
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
.
.
Block 1
Block 3
Block 5
Block 7
.
.
Mirror 1
Mirror 3
Mirror 5
Mirror 7
.
.
Striping
Mirror
Striping
Block 2
Block 4
Block 6
Block 8
.
.
Mirror 2
Mirror 4
Mirror 6
Mirror 8
.
.
RAID (0+1)
Minimum Disks required 4
Capacity N/2
Redundancy Yes
RAID (0+1) combines RAID 0 and RAID 1 - Mirroring and Striping.
RAID (0+1) allows multiple drive failure because of the full redundancy
of the hard drives. If there are more than two hard drives assigned to
perform RAID 1, RAID (0+1) will be performed automatically.
"RAID (0+1)" will not appear in the list of RAID
levels supported by the controller. If you wish
to perform RAID 1, the controller will determine
whether to perform RAID 1 or RAID (0+1). This
will depend on the drive number that has been
selected for the logical drive.
Chapter 3 Functional Descriptions
11
RAID 3 Disk Striping with Dedicated Parity Disk
Logical Drive Physical Disks
Dedicated
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
.
.
Block 1
Block 3
Block 5
Block 7
.
.
Striping
Block 2
Block 4
Block 6
Block 8
.
.
Parity
Parity (1,2)
Parity (3,4)
Parity (5,6)
Parity (7,8)
.
.
RAID 3
Minimum Disks required 3
Capacity N-1
Redundancy Yes
RAID 3 performs Block Striping with Dedicated Parity. One drive
member is dedicated to storing the parity data. When a drive member
fails, the controller can recover/regenerate the lost data of the failed
drive from the dedicated parity drive.
12
User’s Guide
Loading...